Compound-wound dynamo-electric machine



(No Model.)

B. THOMSON. COMPOUND WOUND DYNAMO ELECTRIC MACHINE. No. 349,912. Patented Sept. 28, 1886.

WITNESSES: 4 INVENTOR M m0.

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UNITED STATES PATENT ()FFICE.

ELIHU THOMSON, OF LYNN, MASSACHUSETTS.

COMPOUND-WOUND DYNA MO-ELECTRlC MACHINE.

SPECIFICATION forming part of Letters Patent No. 349,912, dated September 28, 1886.

Application filed June 14, 1886. Serial No. 205,165.

To aZZ 20710722 it may concern:

Be it know-:11 that l, ELIHU THOMSON, a citizen of the United States, and a resident of Lynn, in the county of Essex and State of Massachusetts, have invented certain new and use ful OompoundWVound Dynamos, of which the following is a specification.

Mypresent invention relates to compoundwound dynamos and attachments,whereby the properties of such machines may be varied to suit varied conditions of working.

It is usual to wind compound-wound machines in such a way that as more load is thrown on in multiple arc the volts potential at the terminals rises a little so as to compensate for the drop in the mains to some degree, and so preserve an average flow of current in the multiple-arc branches and an average brilliancy of lights when incandescent lamps are employed.

It is sometimes desirable to feed lamps at a considerable distance from the dynamo, in which case, to save copper, the mains can be made so small as to involve, with full load, a loss of five, ten, fifteen, or even twenty per cent. of the energy of the current when power is cheap. This loss necessitates an increase in volts at the machine of five, ten, fifteen, or twenty per cent., as the case may be; but if in such case the load or number of lamps were lessened, the loss would disappear and too high potential would reach the distant points on the mains. The case assumed is onein which the work is done by current supplied from a distributing center or centers and taken from the mains at a considerable distance from the generating-station. The coarse wire or direct fieldwire winding of a compound-wound machine for such uses I make of such exciting strength that fromlight load to full load of currentgives an increasing potential at the machine terminals up to, say, twenty per cent. I then provide means, such as resistance-slnints, around the whole or part of said winding, so that it may be lowered in effect by such shunting devices to the desired degree required for the circumstances of each case.

Figure 1 shows an arrangement of circuits and apparatus embodying my invention. Fig. 2 is a diagram of circuits. Fig. 3 is a side view of a form of attachment for shunting the direct (No model.)

field; Figs. 4 and 5, other views of the same. Figs. 6, 7, and 8 show other modifications.

In Figs. 1 and 2 S is the derived-circuit fieldcoil.

D D are the direct-circuit coils of a compound-wound machine. Coils D are shown in Fig. 1 as surrounding only the movable armature core, though in the cases where it is used on the field-cores the further attachments are the same.

A is the armature. Y The coils D D are in the main circuit, an of amount of strength to give an increase of potential on passage from light load or nolamps to full load or alllamps on,which increase shall be enough, or more than enough, for all practical requirements. Connections P P are arranged so that a shunt, S, may be used to afford aby-pass for current around coils D D,in whole or part, as desired, said connections being suitably placed for attachment of one or another of a set of shunts, S, giving definitelylessened effects to the coils D D, so that the increase of potential may be less and less as such shunts are of less and less resistance, down, it may be, to a shunt giving practically constant potential at the terminals of the machine from light load to full load. The shunt S is made easy of attachment by clamps P P, fixed to a board, R, as indicated in Fig. 3, and may consist of astrip of German silver or cop per folded on itself and furnished with ears 6 c, Fig. 4, for attachment in any usual way. Other shunts are constructed with less resistances, (as less folds,) Fig. 5, to be substituted for S,when it is necessary to further lower the compound ing. Again, if desired, a set of shunts, as in Fig. 6, can be arranged on a board, with plugs f/ g, to shunt one or the other of them when not needed; or the shunts may be combined in multiple, as in Fig. 7, where metallic strips WV W, with clamps, are shown for the purpose, and may be removcd,or used singly or in pairs, or all together, to obtain the desired properties. Further, the shunts may be arranged as an adjustable rheostat with an operating-handle, as in Fig. 8. This form is especially useful for rapid adaptations to varying potentials or compounding.

hat I claim as my invention is- 1. The combination, in a compound-wound shunt-connections from the same to a set of clamping devices and a set of attachable resistances of graduated amounts, each adapted for connection to the clamping devices.

Signed at Lynn, in the county of Essex and 1 5 dynamo-machine, of a direct-circuit coil of proper power to give a Considerable increase of potential in passing from light to full load, and shunting devices whereby the exciting power of said coil may be lessened to adapt State of Massachusetts, this 10th day of J une,

the machine for use in conditions where a lesser A. D. 1886.

increase of potential is required as and for the purpose set forth. ELIHU THOMSON 2. The combination, with the direct-circuit Witnesses:

M. L. THoMsoN,

field-coil in a compound-wound dynamo, of

O. S. THOMSON. 

